Roof support



March 29, 1966 M. c. POTTS ETAL 3,243,162

ROOF SUPPORT Filed June 26, 1963 BY MI M ,4- Tra/m 5 rs United States Patent 3,243,162 ROOF SUPPORT Michael Charles Potts, Prestbury, Cheltenham, and Wesley Horace Barrett, Cheltenham, England, assignors to Dowty Mining Equipment Limited, Ashchurch, near Tewkesbury, England, a British company Filed June 26, 1963, Ser. No. 290,814 Claims priority, application Great Britain, June 29, 1962, 25,092/ 62 Claims. (Cl. 254189) This invention relates to roof supports suitable for use in mines and is concerned with an arrangement for advancing a roof support towards an anchorage which, in a mine, may be a conveyor which extends along the working face of the mine.

The present invention provides a roof support including an extendable and contractable jack and two flexible hauling elements, one end of each of which is secured to a part of the support and the other end whereof is securable to an anchorage, the jack and the hauling elements being located symmetrically of the jack, and arranged in such a manner that, when the other end of the hauling elements is secured to the anchorage, the jack can be caused to alter in length and act upon the hauling elements equally and simultaneously to advance the support towards the anchorage in a manner that counters any tendency of the unguided roof support to slew about.

The jack may be housed within the support in such a manner that even when it is fully extended it dOes not project from the support. The jack is thus protected from damage.

One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, of which,

FIGURE 1 is a side view, partly in section, of a roof support secured to a conveyor,

FIGURE 2 is a diagrammatic plan view of the sole beam of the roof support, showing the arrangement of the jack and hauling elements and,

FIGURE 3 is a diagrammatic side view of the sole beam.

With reference to the accompanying drawing a roof support suitable for use in a coal mine includes a groundengaging sole beam 1 carrying at least two hydraulicallyoperable telescopic props 2. The props 2 carry a roof bar 3 which can be forced against the roof of the coal mine by extending the props 2.

A hydraulically-operable extendable and contractable jack 4 includes a cylinder 5 secured within the sole beam 1 to its forward end portion by mountings 6, and a jack rod 7 which projects from the rear end of the cylinder 5 towards the rear end of the sole beam 1 and is carried by a piston (not shown) within the cylinder 5. The jack 4 can be extended by supplying hydraulic fluid under pressure to the forward end portion of the cylinder 5. The jack 4 is of such a length that even when it is fully extended it does not project from the sole beam 1.

The hydraulic connections to the props 2 and jack 4 have not been shown in the drawing.

A flexible hauling element 8 in the form of a rope or chain has one end 9 secured to the front end 12 of the sole beam 1. The hauling element 8 passes over a rotatable pulley 11 secured to the end of the jack rod 7 which projects from the cylinder 5 and then extends through the front end 12 of the sole beam 1 towards a conveyor 13 which extends along the working face of the mine. The other end 14 of the hauling element 8 is secured to the conveyor.

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A second flexible hauling element 15 in the form of a rope or chain has one end 16 secured to the front end 12 of the sole beam 1 on the opposite side of the jack 4 to the end 9 of the other hauling element 8 so that, starting with the end 9 or 16 secured to the sole beam 1, the hauling element 8 passes around the pulley 11 in the opposite direction to which the other hauling element 15 passes around a similar rotatable pulley 17 secured to the jack rod 7. The two hauling elements 8, 15 emerge from the front end 12 of the sole beam 1 on opposite sides of the jack 4 to one another. This construction provides a symmetrical arrangement about the jack 4.

In the drawing the conveyor 13 is in an advanced position relative to the roof support and the hauling elements 8, 15 are taut with the jack 4 fully contracted. The roof support can be advanced towards the conveyor 13 by releasing the roof support from the roof and then extending the jack 4. The jack rod 7 moves towards the rear end 10 of the sole beam 1 and, since the hauling elements 8, 15 pass around the pulleys 11, 17 on the end of the jack rod 7, this movement of the jack rod 7 shortens the length of the hauling elements 8, 15 between the front end 12 of the sole beam 1 and the conveyor 13 by an amount which is twice the stroke of the jack rod 7. As the conveyor 13 acts as an anchorage, the roof support is therefore caused to advance towards the conveyor 13 by a distance which is twice the stroke of the jack rod 7.

Since the roof support is connected to the conveyor 13 by two laterally-spaced hauling elements 8, 15 which are both acted upon by the jack 4, any tendency for the roof support to slew, while it is advancing, from a straight line of advance will be reduced. If the roof support tends to slew to the left or right, one of the hauling elements 8, 15 will slacken, and the jack 4 will exert a larger force on the other hauling element and oppose the slewing tendency.

The jack 4 is returned to its contracted condition by the advance of the conveyor 13, the conveyor advance being brought about in any desired manner.

In the arrangement described above, the support is advanced by extending the jack 4. Itis also within the scope of the invention to so arrange the jack 4 that the support is advanced by contracting the jack, for example by securing the end of the jack 4 with the mountings 6 to the rear end portion of the sole beam 1.

We claim as our invention:

1. Mining apparatus including an anchorage means extending along a working face, and an unguided roof support disposed substantially perpendicularly to said anchorage means, said mining apparatus including additionally two cables spaced apart lengthwise of the anchorage means and connecting the roof support, at two points similarly spaced apart, to the anchorage means, and jack means connected to both said cables, and operable to tension both cables simultaneously and equally and thereby to draw the roof support towards the anchorage means, and by their cooperation to correct any tendency for the roof support to slew about.

2. Mining apparatus as in claim 1, wherein the jack means includes a first member mounted upon the roof support and a second member extensible relative to the first member, and operatively connected to the two cables to tension both.

3. Mining apparatus as in claim 2, wherein the first member of the jack means, at its end nearer the anchorage means, is anchored to the roof support, and the second member extends in the direction away from the anchorage member, pulley means carried by the second member and movable, as the latter extends, away from the anchorage means, the two cables being secured to the roof support at opposite sides of the pulley means, and extending in opposite directions about the latter and back to similarly spaced connections to the anchorage means.

4. Mining apparatus as in claim 2, wherein the jack is housed within the roof support, and is of a length, when fully extended, that it does not project from the support.

References Cited by the Examiner UNITED STATES PATENTS 5. Mining apparatus as in claim 1, wherein the roof 1O EVON C. BLUNK, Primary Examiner.

SAMUEL F. COLEMAN, Examiner.

H. C. HORNSBY, Assistant Examiner.

support includes a sole beam engageable with the mine floor, the jack being Wholly enclosed within said sole beam in its extended as Well as in its contracted condition. 

1. MINING APPARATUS INCLUDING AN ANCHORAGE MEANS EXTENDING ALONG A WORKING FACE, AND AN UNGUIDED ROOF SUPPORT DISPOSED SUBSTANTIALLY PERPENDICULARLY TO SAID ANCHORAGE MEANS, SAID MINING APPARATUS INCLUDING ADDITIONALLY TWO CABLES SPACED APART LENGTHWISE OF THE ANCHORAGE MEANS AND CONNECTING THE ROOF SUPPORT, AT TWO POINTS SIMILARLIY SPACED APART, TO THE ANCHORAGE MEANS, AND JACK MEANS CONNECTED TO BOTH CABLES, AND OPERABLE TO 